大肠埃希菌临床分离株的基因组结构分型研究

目的 通过基因组结构分析对临床分离的大肠埃希茵进行分型，并探讨型别与临床疾病的关系。方法 取临床不同疾病病人的痰、尿、血、分泌物等标本，分离大肠埃希菌。用I-CeuI酶切全基因组DNA以及用脉冲场凝胶电泳分离DNA片段后，根据酶切图谱的异同进行分型。结果 从临床上分离的64株大肠埃希菌中，62株有7个I-CeuI酶切住点，2株有8个I-CeuI酶切位点。菌株间I-CeuI酶切图谱差异明显。这些菌株根据基因组结构的差异分为32个型，某些疾病与特定基因组型密切相关。结论 临床分离的大肠埃希菌基因组结构存在多样性，其与临床疾病之间存在一定的对应关系，但尚需大宗病例进一步研究。

GENOMIC TYPING OF CLINICAL ISOLATES OF ESCHERICHIA COLI

Objective We attempted to resolve different genomic types of clinical isolates of E. coli by analysis of genome structure and investigate the relationships between the genomic types and the kinds of associated diseases. Methods E. coli strains were isolated from hospitalized patients with different kinds of infections. Intact bacterial genomic DNA was isolated in agarose blocks and cleaved with I-CeuI. After separation of the fragments by pulsed field gel electrophoresis (PFGE), cleavage patterns of the genomic DNA were compared among the bacteria and the clinical isolates were divided into different genomic types based on their similarities in the I-CeuI cleavage pattern.Results Among the 64 clinical isolates identified as E. coli, 62 had 7 I-CeuI sites and two had 8 I-CeuI sites. These bacteria had obviously different genome structuses and were divided into 32 genome types. The result just as we predict that some certain diseases were closely related to some types.Conclusion There was a significant diversity in genome structure among the clinical isolates of E. coli. There was some extend parallelism relationship between the genome types and clinical diseases.however, this tentative conclusion should be tested extensively.